Anisotropy and Fiber Orientation: A Key Player in the Lateral Imbibition of Cellulose Paper

In this article, we delve into the influence of fiber orientation (structural anisotropy) on paper imbibition, with a particular focus on in-plane imbibition. Utilizing the XLPA experimental method, we analyze several papers with different anisotropies, employing a constant volume of ethanol as the imbibing fluid. Our findings contribute novel insights into the anisotropic behavior of imbibition, a topic not extensively covered in the literature. We analyze how the orientation of fibers significantly influences lateral imbibition, providing a deeper understanding of the microfluidic properties of paper. The anisotropies found for imbibition fit perfectly with the existing data found in the literature, indicating the influence of fiber orientation. Furthermore, the kinetics are shown to be linked directly with the porosity.